Oil pump control system for vehicle and operation method thereof

ABSTRACT

An oil pump control system for a vehicle includes: an oil pump to form a pressure for supplying oil to an engine, an oil pressure adjustment valve to control a pressure of the oil supplied to the engine by controlling the pressure formed by the oil pump, an oil sensor to sense the pressure and temperature of the oil supplied to the engine, and a controller to monitor vehicle information inputted from outside and the oil pressure and temperature sensed by the oil sensor, determine a target oil pressure value based on engine RPM of the monitored vehicle information and the oil temperature, and control the oil pressure adjustment valve such that the monitored oil pressure follows the determined target oil pressure value.

CROSS-REFERENCE(S) TO RELATED APPLICATIONS

The present application claims priority to Korean Patent Application No. 10-2012-0030958, filed on Mar. 27, 2012, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Exemplary embodiments of the present invention relate to an oil pump control system for a vehicle; and, particularly, to an oil pump control system for a vehicle, which controls an oil pump to adjust the oil pressure of an engine lubrication system, and an operation method thereof.

2. Description of Related Art

A conventional oil pump control system for a vehicle includes one or two chambers, and controls the oil pressure of an engine lubrication system using a mechanical spring constant and a pressure applied to the chambers.

The conventional oil pump control system for a vehicle performs control using only a fixed oil pressure, according to such a mechanical control method. Therefore, when the conventional oil pump control is applied to a diesel engine at low engine RPM, the efficiency thereof decreases.

Furthermore, the conventional oil pump control system has a kind of trade-off between a variable start point of a pump and a maximum oil pressure. Therefore, when the variable start point of an oil pressure is set to a low pressure, it is difficult to adjust the oil pressure during full load, and when the oil pressure during full load is adjusted, the variable start point of the oil pressure increases. Accordingly, the fuel efficiency decreases.

The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing an oil pump control system for a vehicle, which is capable of improving the fuel efficiency of an engine by actively controlling a flow rate of an oil pump using engine RPM and internal temperature variables of an oil temperature sensor or engine control unit (ECU).

Other objects and advantages of the present invention can be understood by the following description, and become apparent with reference to the embodiments of the present invention. Also, it is obvious to those skilled in the art to which the present invention pertains that the objects and advantages of the present invention can be realized by the means as claimed and combinations thereof.

In an aspect of the present invention, an oil pump control system for a vehicle, may include an oil pump to form a pressure for supplying oil to an engine, an oil pressure adjustment valve fluid-connected to the oil pump to control a pressure of the oil supplied to the engine by controlling the pressure formed by the oil pump, an oil sensor to sense the pressure and an temperature of the oil supplied to the engine, and a controller to monitor a vehicle information inputted from outside and the pressure and the temperature sensed by the oil sensor, wherein the controller determines a target oil pressure value based on an engine RPM of a monitored vehicle information and the oil temperature, and control the oil pressure adjustment valve such that a monitored oil pressure follows a determined target oil pressure value.

The oil pump may include a first chamber connected to an oil pump outlet fluid-connecting to the engine and a second chamber connected to the oil pressure adjustment valve, wherein an internal pressure of the second chamber is controlled by the oil pressure adjustment valve.

The oil pressure adjustment valve may include a three-port two-way solenoid valve having a P port connected to a first branch diverging from the oil pump outlet, an A port connected to the second chamber, and a T port connected to an oil pan.

The oil pressure adjustment valve may include a three-port two-way solenoid valve having a P port connected to a second branch diverging from a main gallery connected to the first chamber, an A port connected to the second chamber, and a T port connected to an oil pan.

The controller monitors whether the oil sensor and the oil pressure adjustment valve are normal or not, and when functions of the oil sensor and the oil pressure adjustment valve are normal as a result of monitoring, the controller performs a first mode in which the controller determines a first target oil pressure value based on the engine RPM and the oil pressure, and controls the oil pressure adjustment valve such that the monitored oil pressure follows a determined first target oil pressure value.

The controller monitors whether the oil sensor and the oil pressure adjustment valve are normal or not, and when functions of the oil sensor and the oil pressure adjustment valve are normal as a result of monitoring, the controller performs a first mode in which the controller determines a first target oil pressure value based on the engine RPM and the oil pressure, and controls the oil pressure adjustment valve such that a monitored oil pressure follows a determined first target oil pressure value.

When an oil temperature sensing function of the oil sensor is abnormal as a result of monitoring, the controller performs a second mode in which the controller determines a second target oil pressure value based on the engine RPM, and controls the oil pressure adjustment valve such that the monitored oil pressure follows a determined second target oil pressure valve.

When at least one of an oil pressure sensing function of the oil sensor and the function of the oil pressure adjustment valve is abnormal as a result of monitoring, the controller performs a third mode in which the controller deactivates a control function for the oil pressure adjustment valve.

The oil pump operates as a mechanical variable oil pump.

The target oil pressure value is determined by a first map in which the target oil pressure value is predetermined for the engine RPM and the oil temperature.

The target oil pressure value of the first map is decided by linear interpolation.

The oil sensor is constructed to may have both of an oil pressure sensing function and an oil temperature sensing function or may have any one of the oil pressure sensing function and the oil temperature sensing function.

In another aspect of the present invention, an operation method of an oil pump control system for a vehicle, which may include an oil pump to form a pressure for supplying oil to an engine and an oil pressure adjustment valve connected to the oil pump to control a pressure of the oil supplied to the engine by controlling the pressure formed by the oil pump, the operation method including monitoring a vehicle information inputted from outside and an oil pressure and an oil temperature sensed by an oil sensor, determining a target oil pressure value based on an engine RPM of a monitored vehicle information and the oil temperature, and controlling the oil pressure adjustment valve such that a monitored oil pressure follows a determined target oil pressure value.

The operation method may further include monitoring whether the oil sensor and the oil pressure adjustment valve are normal or not, and when functions of the oil sensor and the oil pressure adjustment valve are normal as a result of monitoring, performing a first mode in which a first target oil pressure value is determined based on the engine RPM and the oil temperature and the oil pressure adjustment valve is controlled such that the monitored oil pressure follows a determined first target oil pressure value.

When an oil temperature sensing function of the oil sensor is abnormal as a result of monitoring, performing a second mode in which a second target oil pressure value is determined based on the engine RPM and the oil pressure adjustment valve is controlled such that the monitored oil pressure follows a determined second target oil pressure value.

When at least one of an oil pressure sensing function of the oil sensor and the function of the oil pressure adjustment valve is abnormal as a result of monitoring, performing a third mode in which a control function for the oil pressure adjustment valve is deactivated.

The oil pump may include a first chamber connected to an oil pump outlet fluid-communicating to the engine and a second chamber connected to the oil adjustment valve, wherein an internal pressure of the second chamber is controlled by the oil pressure adjustment valve.

The oil pump may include a first chamber connected to an oil pump outlet fluid-communicating to the engine and a second chamber connected to the oil adjustment valve, wherein an internal pressure of the second chamber is controlled by the oil pressure adjustment valve.

The oil pressure adjustment valve may include a three-port two-way solenoid valve having a P port connected to a first branch diverging from the oil pump outlet, an A port connected to the second chamber, and a T port connected to an oil pan.

The oil pressure adjustment valve may include a three-port two-way solenoid valve having a P port connected to a second branch diverging from a main gallery connected to the first chamber, an A port connected to the second chamber, and a T port connected to an oil pan.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an oil pump control system for a vehicle in accordance with various exemplary embodiments of the present invention.

FIG. 2 is a block diagram of a controller in a first mode in accordance with the various exemplary embodiments of the present invention.

FIG. 3 is a state diagram of an oil pressure adjustment valve in the first mode in accordance with the various exemplary embodiments of the present invention.

FIG. 4 is a graph showing oil pressures in the first mode in accordance with the various exemplary embodiments of the present invention.

FIG. 5 is another state diagram of the oil pressure adjustment valve in the first mode in accordance with the various exemplary embodiments of the present invention.

FIG. 6 is another graph showing oil pressures in the first mode in accordance with the various exemplary embodiments of the present invention.

FIG. 7 is a block diagram of the controller in a second mode in accordance with the various exemplary embodiments of the present invention.

FIG. 8 is a state diagram of the oil pressure adjustment valve in the second mode in accordance with the various exemplary embodiments of the present invention.

FIG. 9 is a graph of oil pressures in the second mode in accordance with the various exemplary embodiments of the present invention.

FIG. 10 is an operation state diagram explaining an operation method of the oil pump control system for a vehicle in accordance with the various exemplary embodiments of the present invention.

FIG. 11 is a block diagram of an oil pump control system for a vehicle in accordance with various exemplary embodiments of the present invention.

FIG. 12 is a graph showing effects in accordance with the exemplary embodiments of the present invention.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Throughout the disclosure, like reference numerals refer to like parts throughout the various figures and embodiments of the present invention.

Referring to FIG. 1, an oil pump control system for a vehicle in accordance with a first embodiment of the present invention will be described. FIG. 1 is a block diagram of the oil pump control system for a vehicle in accordance with the first embodiment of the present invention.

The oil pump control system 100 for a vehicle in accordance with the first embodiment of the present invention may include an oil pump 110, an oil pressure adjustment valve 120, an oil sensor 130, and a controller 140.

The oil pump 110 pumps oil of an oil pan, and discharges the pumped oil to an oil pump outlet 112. The oil pump 110 performs a function of forming a pressure for supplying oil to an engine E.

In the present exemplary embodiment of the present invention, the oil pump 110 may include a first chamber 114 connected to the oil pump outlet 112 and a second chamber 116 connected to the oil pressure adjustment valve 120 to control the internal pressure thereof.

The oil pressure control valve 120 may include a three-port two-way solenoid valve having a P port connected to a first branch D1 diverging from the oil pump outlet 112, an A port connected to the second chamber 116, and a T port connected to the oil pan. In this case, the pressure of oil supplied through the first branch D1 is used as a pressure source of the oil pressure adjustment valve 120.

The oil sensor 130 senses the pressure and temperature of oil supplied to the engine E through a main gallery M, and transfers the sensed pressure and temperature to the controller 140. Furthermore, the oil sensor 130 checks whether its function is normal or not, and transfers the check result to the controller 130.

That is, the oil sensor 130 may have an oil pressure sensing function for sensing the pressure of oil, an oil temperature sensing function for sensing the temperature of oil, and a function of determining whether the oil sensor 130 is normal or not. The oil sensor 130 may be constructed to include both of the oil pressure sensing function and the oil temperature sensing function or include only any one of the functions.

The controller 140 controls overall operations of the oil pump control system 100 for a vehicle in accordance with the first embodiment of the present invention. The controller 140 monitors vehicle information inputted from outside and the oil pressure and temperature sensed by the oil sensor 130, calculates a target oil pressure value based on an engine RPM of the monitored vehicle information and the oil temperature, and controls the oil pressure adjustment valve 120 such that the monitored oil pressure follows the calculated target oil pressure value. The controller 140 may be included in an engine control unit (ECU) or provided as a separate module.

Furthermore, the controller 140 may monitor whether the oil sensor 130 and the oil pressure adjustment valve 120 are normal or not, and operate in three modes according to the monitoring result.

As a result of monitoring, when the functions of the oil sensor 130 and the oil pressure adjustment valve 120 are normal, the controller 140 operates in a first mode. In the first mode, the controller 140 controls the pressure of oil supplied to the engine E based on the engine RPM and the oil temperature. The first mode corresponds to a normal mode of the oil pump control system 100 for a vehicle in accordance with the first embodiment of the present invention.

Referring to FIG. 2, the controller 140 may include a first map 142 and a first PID control module 144, in order to perform the first mode. A first target oil pressure value may be calculated by the first map 142 in which a target oil pressure value is previously decided for the engine RPM and the oil pressure. The first PID control module 144 controls the oil pressure adjustment valve 120 such that the monitored oil pressure follows the calculated first target oil pressure value.

Referring to FIG. 3, when the pressure of oil supplied to the engine E is controlled to a low pressure in the first mode, the oil flows from the P port to the A port of the oil pressure adjustment valve 120. Accordingly, when the pressure of the oil supplied to the engine E is controlled to a low pressure in the first mode, the oil pressures of the first chamber 114, the second chamber 116, and the main gallery M may be represented as shown in FIG. 4.

Referring to FIG. 5, when the pressure of the oil supplied to the engine E is controlled to the first target oil pressure value calculated by the first map 142 in the first mode, the oil flows from the P port to the A port and from the A port to the P port of the oil pressure relief value 120. The target oil pressure value which is previously set in the first map 142 may be decided by linear interpolation.

Accordingly, when the pressure of the oil supplied to the engine E is controlled to the first target oil pressure value in the first mode, the oil pressures of the first chamber 114, the second chamber 116, and the main gallery M may be represented as shown in FIG. 6.

As a result of monitoring, when the oil temperature sensing function of the oil sensor 130 is abnormal, the controller 140 operates in a second mode. In the second mode, the controller 140 controls the pressure of the oil supplied to the engine E based on the engine RPM. The second mode corresponds to an operation mode which is performed when the oil temperature sensing function corresponding to a partial function of the oil sensor 130 of the oil pump control system 100 in accordance with the first embodiment of the present invention is out of order.

Referring to FIG. 7, the controller 140 may include a second curve 146 and a second PID control module 148, in order to perform the second mode. A second target oil pressure value may be calculated by the second curve 146 in which a target oil pressure value is previously decided for the engine RPM. The second PID control module 148 controls the oil pressure adjustment valve 120 such that the monitored oil pressure follows the calculated second target oil pressure value.

Referring to FIG. 5, when the pressure of the oil supplied to the engine E is controlled to the second target oil pressure value calculated by the second curve 146 in the second mode, the oil flows from the P port to the A port and from the A port to the P port of the oil pressure adjustment valve 120. The target oil pressure value preset in the second curve 146 may be decided by linear interpolation. The first map 142 is a two-dimensional map where the engine RPM and the oil pressure are set to input values, whereas the second curve 146 is a one-dimensional curve function where the engine PPM is set to an input value.

Accordingly, when the pressure of the oil supplied to the engine E is controlled to the second target oil pressure value in the second mode, the oil pressures of the first chamber 114, the second chamber 116, and the main gallery M may be represented as shown in FIG. 6.

As a result of monitoring, when at least any one of the oil pressure sensing function of the oil sensor 130 and the function of the oil pressure adjustment valve 120 is abnormal, the controller 140 operates in a third mode. In the third mode, the controller 140 may deactivate a control function for the oil pressure adjustment valve 120.

Referring to FIG. 8, when the pressure of the oil supplied to the engine E is set to a maximum pressure to turn off the control and electronic control function in the third mode, the oil flows from the A port to the T port of the oil pressure adjustment valve 120, and is then discharged to the oil pan.

Accordingly, when the pressure of the oil supplied to the engine E is set to the maximum pressure to turn off the control and electronic control function in the third mode, the oil pressures of the first chamber 114, the second chamber 116, and the main gallery M may be represented as shown in FIG. 9.

FIG. 10 is a state diagram based on the above-described three operation modes. Referring to FIG. 10, an operation method of the oil pump control system 100 for a vehicle in accordance with the exemplary embodiment of the present invention will be described.

Referring to FIG. 10, when the initialization of the system is completed in a state where the engine E is operated, the controller 140 continuously monitors whether the oil sensor 130 and the oil pressure adjustment valve 120 are normal or not, and selectively performs the first mode S1, the second mode S2, and the third mode S3 according to the monitoring result.

For example, as a result of monitoring, when the functions of the oil sensor 130 and the oil pressure relief value 120 are normal in the initial state of the system, the controller 140 immediately performs the first mode S1. When the functions of the oil sensor 130 and the oil pressure relief value 120 are normal in a state where the system is performing the second or third mode S2 or S3, the controller 140 transits to the first mode S1 as shown in FIG. 10.

Furthermore, as a result of monitoring, when the oil temperature sensing function of the oil sensor 130 is abnormal in the initial state of the system, the controller 140 immediately performs the second mode S2. When the oil temperature sensing function of the oil sensor 130 is abnormal in a state where the system is performing the first or third mode S1 or S3, the controller 140 transits to the second mode S2 as shown in FIG. 10.

Furthermore, as a result of monitoring, when at least any one of the oil pressure sensing function of the oil sensor 130 and the function of the oil pressure adjustment valve 120 is abnormal in the initial state of the system, the controller 140 immediately performs the third mode S3. When at least any one of the oil pressure sensing function of the oil sensor 130 and the function of the oil pressure adjustment valve 120 is abnormal in a state where the system is performing the second or third mode S2 or S3, the controller 140 transits to the third mode S3 as shown in FIG. 10.

Hereinafter, referring to FIG. 11, an oil pump control system 200 for a vehicle in accordance with a second embodiment of the present invention will be described. The oil pump control system 200 for a vehicle in accordance with the second embodiment of the present invention may include an oil pump 210, an oil pressure adjustment valve 220, an oil sensor 230, and a controller 240.

The oil pump 210 pumps oil of an oil pan, and discharges the pumped oil to an oil pump outlet 212. The oil pump 210 performs a function of forming a pressure for supplying oil to an engine E.

In the present exemplary embodiment of the present invention, the oil pump 210 may include a first chamber 214 connected to the oil pump outlet 212 and a second chamber 216 connected to the oil pressure adjustment valve 220 to control the internal pressure thereof.

The oil pressure relief value 220 may include a three-port two-way solenoid valve which has a P port connected to a second branch D2 diverging from a main gallery M, an A port connected to the second chamber 216, and a T port connected to the oil pan. In this case, the pressure of oil supplied through the second branch D2 is used as a pressure source of the oil pressure adjustment valve 220.

In the oil pump control system 200 in accordance with the second embodiment of the present invention, the pressure source of the oil pressure adjustment valve 220 is connected to the main gallery M, unlike the oil pump control system 100 in accordance with the first embodiment of the present invention.

The oil pump control systems 100 and 200 for a vehicle in accordance with the exemplary embodiments of the present invention may actively control the oil pressure to a desired level, as shown in FIG. 12. Therefore, since the oil pump control systems 100 and 200 may reduce the oil pressure to a desired level (high-temperature full-load level) in a state where the oil temperature is low, a driving torque required for oil pressure/flow rate formation may be reduced to thereby improve engine fuel efficiency.

Furthermore, although a fail occurs in the electronic control system, the oil pump control systems 100 and 200 for a vehicle in accordance with the exemplary embodiments of the present invention operate in the same manner as a mechanical one-stage variable oil pump with a relief valve. Therefore, the oil pump control systems 100 and 200 have an advantage in terms of fail safety.

In accordance with the exemplary embodiments of the present invention, the oil pump control system for a vehicle and the operation method thereof may actively control the flow rate of the oil pump using the engine RPM and the internal temperature variables of the oil temperature sensor or the controller, thereby improving the fuel efficiency of the engine.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

What is claimed is:
 1. An oil pump control system for a vehicle, comprising: an oil pump to form a pressure for supplying oil to an engine; an oil pressure adjustment valve fluid-connected to the oil pump to control a pressure of the oil supplied to the engine by controlling the pressure formed by the oil pump; an oil sensor to sense the pressure and an temperature of the oil supplied to the engine; and a controller to monitor a vehicle information inputted from outside and the pressure and the temperature sensed by the oil sensor, wherein the controller determines a target oil pressure value based on an engine RPM of a monitored vehicle information and the oil temperature, and control the oil pressure adjustment valve such that a monitored oil pressure follows a determined target oil pressure value.
 2. The oil pump control system of claim 1, wherein the oil pump includes a first chamber connected to an oil pump outlet fluid-connecting to the engine and a second chamber connected to the oil pressure adjustment valve, wherein an internal pressure of the second chamber is controlled by the oil pressure adjustment valve.
 3. The oil pump control system of claim 2, wherein the oil pressure adjustment valve includes a three-port two-way solenoid valve having a P port connected to a first branch diverging from the oil pump outlet, an A port connected to the second chamber, and a T port connected to an oil pan.
 4. The oil pump control system of claim 2, wherein the oil pressure adjustment valve includes a three-port two-way solenoid valve having a P port connected to a second branch diverging from a main gallery connected to the first chamber, an A port connected to the second chamber, and a T port connected to an oil pan.
 5. The oil pump control system of claim 1, wherein the controller monitors whether the oil sensor and the oil pressure adjustment valve are normal or not, and when functions of the oil sensor and the oil pressure adjustment valve are normal as a result of monitoring, the controller performs a first mode in which the controller determines a first target oil pressure value based on the engine RPM and the oil pressure, and controls the oil pressure adjustment valve such that the monitored oil pressure follows a determined first target oil pressure value.
 6. The oil pump control system claim 2, wherein the controller monitors whether the oil sensor and the oil pressure adjustment valve are normal or not, and when functions of the oil sensor and the oil pressure adjustment valve are normal as a result of monitoring, the controller performs a first mode in which the controller determines a first target oil pressure value based on the engine RPM and the oil pressure, and controls the oil pressure adjustment valve such that a monitored oil pressure follows a determined first target oil pressure value.
 7. The oil pump control system of claim 6, wherein, when an oil temperature sensing function of the oil sensor is abnormal as a result of monitoring, the controller performs a second mode in which the controller determines a second target oil pressure value based on the engine RPM, and controls the oil pressure adjustment valve such that the monitored oil pressure follows a determined second target oil pressure valve.
 8. The oil pump control system of claim 7, wherein, when at least one of an oil pressure sensing function of the oil sensor and the function of the oil pressure adjustment valve is abnormal as a result of monitoring, the controller performs a third mode in which the controller deactivates a control function for the oil pressure adjustment valve.
 9. The oil pump control system of claim 8, wherein the oil pump operates as a mechanical variable oil pump.
 10. The oil pump control system of claim 1, wherein the target oil pressure value is determined by a first map in which the target oil pressure value is predetermined for the engine RPM and the oil temperature.
 11. The oil pump control system of claim 10, wherein the target oil pressure value of the first map is decided by linear interpolation.
 12. The oil pump control system of claim 1, wherein the oil sensor is constructed to have both of an oil pressure sensing function and an oil temperature sensing function or have any one of the oil pressure sensing function and the oil temperature sensing function.
 13. An operation method of an oil pump control system for a vehicle, which includes an oil pump to form a pressure for supplying oil to an engine and an oil pressure adjustment valve connected to the oil pump to control a pressure of the oil supplied to the engine by controlling the pressure formed by the oil pump, the operation method comprising: monitoring a vehicle information inputted from outside and an oil pressure and an oil temperature sensed by an oil sensor; determining a target oil pressure value based on an engine RPM of a monitored vehicle information and the oil temperature, and controlling the oil pressure adjustment valve such that a monitored oil pressure follows a determined target oil pressure value.
 14. The operation method of claim 13, further including: monitoring whether the oil sensor and the oil pressure adjustment valve are normal or not; and when functions of the oil sensor and the oil pressure adjustment valve are normal as a result of monitoring, performing a first mode in which a first target oil pressure value is determined based on the engine RPM and the oil temperature and the oil pressure adjustment valve is controlled such that the monitored oil pressure follows a determined first target oil pressure value.
 15. The operation method of claim 14, further including, when an oil temperature sensing function of the oil sensor is abnormal as a result of monitoring, performing a second mode in which a second target oil pressure value is determined based on the engine RPM and the oil pressure adjustment valve is controlled such that the monitored oil pressure follows a determined second target oil pressure value.
 16. The operation method of claim 14, further including, when at least one of an oil pressure sensing function of the oil sensor and the function of the oil pressure adjustment valve is abnormal as a result of monitoring, performing a third mode in which a control function for the oil pressure adjustment valve is deactivated.
 17. The operation method of claim 13, wherein the oil pump includes a first chamber connected to an oil pump outlet fluid-communicating to the engine and a second chamber connected to the oil adjustment valve, wherein an internal pressure of the second chamber is controlled by the oil pressure adjustment valve.
 18. The operation method of claim 14, wherein the oil pump includes a first chamber connected to an oil pump outlet fluid-communicating to the engine and a second chamber connected to the oil adjustment valve, wherein an internal pressure of the second chamber is controlled by the oil pressure adjustment valve.
 19. The operation method of claim 18, wherein the oil pressure adjustment valve includes a three-port two-way solenoid valve having a P port connected to a first branch diverging from the oil pump outlet, an A port connected to the second chamber, and a T port connected to an oil pan.
 20. The operation method of claim 18, wherein the oil pressure adjustment valve includes a three-port two-way solenoid valve having a P port connected to a second branch diverging from a main gallery connected to the first chamber, an A port connected to the second chamber, and a T port connected to an oil pan. 